Technical Field
The present invention is directed to modified asphaltenes. The present invention includes a process for reacting crude asphaltene with acid to form an acid-functionalized asphaltene. The acid-functionalized asphaltene has excellent adsorption properties and can be used for removal of dye compounds from aqueous samples.
Description of the Related Art
The “background” description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly or impliedly admitted as prior art against the present invention.
Heavy petroleum residue constitutes about 70% of drilled crude oils. A fairly low percent of these residues is being utilized without much processing. Asphaltenes are a class of molecular substances or components found in crude oil, along with resins, aromatic hydrocarbons and saturates such as alkanes. Although found in insignificant quantities, asphaltenes are nonetheless one of the most notable components present in petroleum due to their precipitation and flocculation properties, which often pose a great challenge towards cracking and refining of crude oil. The tendency of asphaltenes to precipitate during crude oil recovery can cause severe consequences such as a sharp decline in oil flow or even blockage of pipelines and processing equipment. Asphaltenes can also increase the viscosity of oil, which can in turn reduce, or even halt, its flow. Furthermore, asphaltenes are known to be coke precursors in acid catalysis and can act as catalyst inhibitors by catalyst deactivation and catalyst poisoning. As such, asphaltenes pose a serious problem to a variety of processes in the petroleum industry.
It has also been reported that asphaltenes are large molecules and are composed of highly condensed polyaromatic rings bearing long aliphatic and alicyclic peripheral substituents along with metals and heteroatoms as part of a ring system. Asphaltenes are primarily composed of the elements hydrogen and carbon, with one to three sulfur, oxygen, or nitrogen atoms per molecule. The basic structure is composed of rings, mainly aromatics, with three to ten or more rings per molecule that are usually fused together to form the polycyclic core of the molecule. [Hasan, M.; Siddiqui, M. N.; and Arab, M., Fuel, Volume 67, No. 8, August, 1988, p. 1131; Shirokoff, J. W.; Siddiqui, M. N.; and Ali, M. F., Energy & Fuels, Volume 11, 1997, p. 561—each incorporated herein by reference in its entirety].
Contamination from dyes has attracted tremendous attention owing to their negative effects on the environment. These toxic pollutants are nonbiodegradable and can accumulate in the human body causing a variety of diseases and disorders. Dyes such as bromophenol blue and methyl orange, widely used in textile and tannery, can cause anemia, insomnia, renal damages, central nervous system damage and dysfunction of the immune system [G. CamCo-Unal, N. L. B. Pohl, Quantitative Determination of Heavy Metal Contaminant Complexation by the Carbohydrate Polymer Chitin, J. Chem. Eng. Data. 55 (2010) 1117-1121; R. Kiefer, W. H. Höll, Sorption of Heavy Metals onto Selective Ion-Exchange adsorbents with Aminophosphonate Functional Groups, Ind. Eng. Chem. 40 (2001) 4570-4576; G. Güçlü, G. Gürdağ, S. Özgümüş, Competitive removal of heavy metal ions by cellulose graft Copolymers, J. Appl. Polym. SCo. 90 (2003) 2034-2039—each incorporated herein by reference in its entirety]. A variety of techniques like adsorption, precipitation, dialysis, ion exchange, reverse osmosis and extraction, have been reported for the removal of dyes contaminants. One of the most attractive among these techniques is presumably the adsorption process due to the availability of different types of efficient adsorbents [K. KesenCo, R. Say, A. Denizli, Removal of heavy metal ions from water by using poly(ethyleneglyCol dimethacrylate-Co-acrylamide) beads, Eur. Polym. J. 38 (2002) 1443-1448; K. E. Geckeler, Polymer-metal Complexes for environmental protection. Chemoremediation in the aqueous homogeneous phase, Pure. Appl. Chem. 73 (2001) 129-136; W. U. Hong, Y. J. In, M. L. Uo, B. I. Shuping, A Simple and Sensitive Flow-Injection On-line PreConcentration Coupled with Hydride Generation Atomic Fluorescence Spectrometry for the Determination of Ultra-trace Lead in Water, Wine, and Rice, Anal. Chem. 23 (2007) 1109-1112; S. J. Shahtaheri, M. Khadem, F. Golbabaei, A. Rahimi-Froushan, M. R. Ganjali, P. Norouzi, Solid phase extraction for evaluation of occupational exposure to Pb (II) using XAD-4 sorbent prior to atomic absorption spectrosCopy, Int. J. Occup. Saf. Ergo. 13(2007) 137-145—each incorproated herein by reference in its entirety]. Inorganic/organic polymer hybrid adsorbents have been widely investigated, and their efficiency of dyes removal has been attributed to the formation of a stronger chemical bonding between dye and adsorbent, for instance, amine motifs in the hybrid materials [Q. Zhang, B. Pan, W. Zhang, B. Pan, Q. Zhang, Arsenate Removal from Aqueous Media by Nanosized Hydrated Ferric Oxide (HFO)-Loaded Polymeric Sorbents: Effect of HFO Loadings, Ind. Eng. Chem. Res. 47 (2008) 3957-3962; G. P. Kumar, P. A. Kumar, S. Chakraborty, M. Ray, Uptake and desorption of Copper ion using functionalized polymer Coated silica gel in aqueous environment, Sep. Purif. Technol. 57 (2007) 47-56; M. Laatikainen, K. Sirola, E. Paatero, Binding of transition metals by soluble and silica-bound branched poly(ethyleneimine). Part 1. Competitive binding equilibria, Colloid Surface A. 296 (2007) 191-205; Y. Tao, L. Ye, J. Pan, Y. Wang, B. Tang, Removal of Pb(II) from aqueous solution on chitosan/TiO2 hybrid film. J. Hazard. Mater. 161 (2009) 718-22; Z.-Y. He, H.-L. Nie, C. Branford-White, L.-M. Zhu, Y.-T. Zhou, Y. Zheng, Removal of MO from aqueous solution by adsorption onto a novel activated nylon-based membrane, Bioresour. Technol. 99 (2008) 7954-8—each incorporated herein by reference in its entirety].
Research on the chemical reactivity of asphaltene has adopted a two-pronged approach. On one hand, attempts are being made to increase or decrease the solubility of asphaltene so as to mitigate the flocculation properties of asphaltene and its impact on crude oil viscosity or to increase precipitation of asphaltene and thereby its separation from crude oil, respectively. On the other hand, there are ongoing efforts in turning asphaltene into a useful material in industries such as but not limited to polymer and environmental protection. The present disclosure provides a process for chemically modifying asphaltene to produce a functionalized asphaltene with physical properties that are suitable for applications such as but not limited to removal of pollutant compounds from water by adsorption.